Keep in mind that Broadwell is a "Tick" in Intel's "Tick Tock" model. Generally speaking "Tick" processors improve efficiency while "Tock" processors improve performance. As a result I do not expect the MacBook Air and MacBook Pro scores to increase significantly.

MacBook AirSingle-core for the i5 MacBook Airs has increased 6% thanks to the move from Haswell to Broadwell. Multi-core performance for the i5 model increased 7% but interestingly, multi-core performance for the i7 model increased 14%.

John Poole, founder of Primate Labs, strongly recommends purchasing the i7 model over the i5 model. "If you're thinking of buying the new MacBook Air I would strongly recommend the i7 processor. It has 20% faster single-core performance and 25% faster multi-core performance for only a 15% increase in price."

MacBook ProSingle-core performance increases between 3% to 7% from Haswell to Broadwell, depending on the model. Multi-core performance has increased 3% to 6%. The increases in performance are roughly in line with the MacBook Pro's price differences.